# Best sphere model for texturing/rendering?

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I know there are two methods of generating a spherical mesh - the standard one with rings of polygons and a tight knot of triangles meeting at the polar vertices, and the tesselation method where you start with an octahedron or such and sub-divide each triangle repeatedly. My maths may be a little rusty, but I can mentally visualise both methods well enough to be fairly cetain I could model them. What concerns me though, is the benefits and pitfalls of the two types as far as texturing and usage go. The 'standard' one has the benefit of easily rendered triangle-strips, but has the texturing mess of those 'knots' at either pole. Logically, it also seems the easiest one to work with if i wanted to oblate the sphere (these will be for planets). The second type escapes those vertex-pileup 'knots', but I've no idea if its possible to make good triangle-strips on the surface, or will I be forced to just send a triangle-list? On the other hand, it would seem ideally suited to LOD, just tesselating the triangles further as needed as the viewer gets closer. So, the floor is open I guess. I can't see any problems either way with programming one or the other. Texturing them, and knowing their quirks comes from experience, so I figured I ought to ask here :) Yours, Ann-Marie

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It's possible to make strips from the tessellated triangles of an octahedron, although it's a bit more complicated than just using a triangle list... And in practice there shouldn't be a large difference in performance so using a triangle list is OK in most cases.

Texturing the octahedron will be quite a bit different. I would use four textures, each covering two adjacent faces of the original octahedron. Creating the textures may be the biggest hurdle unless you're procedurally generating them. Existing maps of planets like Earth or Mars tend to be in a format that's trivial to use on the "standard" type of sphere but require some kind of conversion to use with a different texturing scheme.

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Normalise a cube.

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